The present invention relates to a lens actuating device, a camera module, and portable electronic equipment and particularly relates to a lens actuating device in which a zooming motor for actuating a zoom lens and a focusing motor for actuating a focusing lens are coaxially disposed, and a camera module and portable electronic equipment in which the lens actuating device is used.
In an imaging apparatus such as video camera and video movie for taking pictures of a subject, generally, a zoom lens for adjusting a perspective of an image of the subject and a focusing lens for adjusting a focus of the image of the subject are provided, and the image of the subject that is to be captured is formed on an imaging device such as CCD.
Among conventional lens actuating devices is a lens actuating device which actuates a zoom lens and a focusing lens in directions of an optical axis. In the lens actuating device for the zoom lens and the focusing lens, a zooming motor and a focusing motor are fixed to first and second different motor mounts, respectively, so that an increased number of components including resin bearings are required, which deteriorates workability in assembling. Besides, the lens actuating device has a problem in that the first and second motor mounts disposed in different directions involve poor utilization of mounting space.
A lens actuating device improved with regard to such problems has been proposed in JP 3410250 B2. In the lens actuating device, as shown in FIG. 6, an imaging lens 102 is fixed on subject side, and a first lens holding frame 104 holding a zoom lens 103 is placed behind the imaging lens 102. The first lens holding frame 104 is guided by upper and lower guide shafts 105, 106 so as to be capable of reciprocating along an optical axis K in directions of arrows X1, X2. On the other hand, a second lens holding frame 108 holding a focusing lens 107 is placed on imaging device side behind the zoom lens 103. The second lens holding frame 108 is guided by the upper and lower guide shafts 105, 106 so as to be capable of reciprocating along the optical axis K in the directions of the arrows X1, X2. Upper end part 104a of the first lens holding frame 104 holding the zoom lens 103 is pinched by a halfnut member 109 in which a halfnut part 109a and a pressing part 109b are integrally formed. Upper end part 108a of the second lens holding frame 108 holding the focusing lens 107 is pinched by a halfnut member 113 in which a halfnut part 113a and a pressing part 113b are integrally formed.
In the vicinity of the upper end part 104a of the first lens holding frame 104 and the upper end part 108a of the second lens holding frame 108 is a motor mount 121. The motor mount 121 is formed of a sheet metal member bent into a shape of a square bracket. A zooming motor 110 is fixed to one lateral side part 121a of the motor mount 121, and a focusing motor 114 is fixed to the other lateral side part 121b facing the one lateral side part 121a of the motor mount 121 across a space. At an intermediate position between the one lateral side part 121a and the other lateral side part 121b of the motor mount 121, bearing hold part 121c for holding a resin bearing 122 is formed integrally with a base part 121d by cutting and bending a part of the base part 121d. The lateral side parts 121a, 121b and the bearing hold part 121c are bent at generally right angles with respect to the base part 121d. 
In the lens actuating device 120 configured in such a manner, the zooming motor 110 for actuating the zoom lens 103 and the focusing motor 114 for actuating the focusing lens 7 are fixed to the single motor mount 121, and a first lead screw 111 of the zooming motor 110 and a second lead screw 115 of the focusing motor 114 are supported by a bearing part (121c, 122) formed at an intermediate position of the motor mount 121 such that the screws can be rotated coaxially and independently. Therefore, the lens actuating device 120 has advantages including not only decrease in number of components and improvement in workability in assembling but also improvement in utilization of mounting space for the motors 110, 114 and reduction in size of the lens actuating device 120, in comparison with conventional devices.
In recent years, small camera modules that make use of solid-state image sensors such as CCD have begun being installed in many types of portable equipment. Such camera modules are required to have drop resistance that prevents destruction of the module in event of drop of the portable equipment, which drop may be caused by a mistake of a user. For example, it is generally said that a drop impact acceleration caused on portable equipment dropped from a height of 1.7 m onto a concrete block is on the order of 6000 G. When an impact caused by the drop or the like of the portable equipment is exerted on the lens actuating device 120 employed in a camera module, moments about the bearing part (121c, 122) formed at the intermediate position of the motor mount 121 are produced on the zooming motor 110 directly connected to the first lead screw 111 and on the focusing motor 114 directly connected to the second lead screw 115. In a camera module for portable equipment, generally, a motor mount is often made of resin instead of metal, in view of weight reduction. Such a resin motor mount has a decreased strength and causes a problem in that the lens actuating device tends to be destructed under influence of the moments.